Johanna Quaas … still puts on an awe-inspiring show at 91.
Photograph: Steve Meddle/REX/Shutterstock

Right now, thousands of perfectly ordinary adults are in online forums airing concerns such as: “Is it necessary to apply the posterior pelvic tilt in the straddled one-arm handstand?” Or: “Pancake stretch: position of the knees?” These are just a couple of the posts by the 32,432 members of the forum on Gymnastic Bodies – an online training programme designed by the former US Olympic gymnastics team coach Christopher Sommer. Profile pictures frequently show off killer abs and favourite (gymnastic) positions, but the tone of the discussions is one of camaraderie and a shared childlike wonder at the cool stuff their bodies are now capable of. Meet the gymnastics geeks.

Gymnastics may sound old-school compared with the high-intensity interval training and Clubbercise classes doing the rounds in gym chains, but many are quietly eschewing the mindless burn in favour of this more progressive approach, using wall bars, rings and ropes, and culminating in a “human flag” (grabbing on to a vertical bar and suspending your body horizontally – the ultimate demonstration of strength).

Before Sommer started writing about his training methods in 2003, “gymnastics training was a closed world”, says Gymnastics Bodies’ sole European affiliate, Wesley Tan. But interest has grown quickly and, in 2010, another online gymnastics-based programme, Gold Medal Bodies Fitness was launched, and it, too, has now also taught tens of thousands of people in their living rooms. Physical classes are also cropping up – Tan runs them through his company, Forma, and some gyms, such as CrossFit, offer adult gymnastics.

Chris Mills, principal lecturer in sport and exercise science at Portsmouth University, is a fan. “Being an adult gymnast myself – I started at age 26, my wife started at age 44 – I am an advocate of adult gymnastics. It has a number of health benefits, including general fitness. It also facilitates the development of muscular strength, flexibility, coordination and balance. Learning new skills and exercises challenges your neuromuscular system and may help adult gymnasts to focus their attention, and improve confidence and judgment.

“There’s some evidence to suggest that regular gymnastics training can improve mobility and posture via improved motor skill coordination,” he adds. “Cognitive function is promoted by the learning of new skills, and learning new routines aids memory. As we age, our bone mineral density decreases. However, regular body-weight exercises, such as gymnastics, can help to maintain bone health.”

Gymnastics Bodies, says Tan, is the “original gymnastics training method”, while adaptations are increasingly called simply “body-weight exercise”. The model and fitness coach Roger Frampton has devised his own gymnastics-inspired “Frampton Method”. His book, The Flexible Body, will join the hordes of exercise books released in January and his Instagram account, with images of him balancing on his hands, toes pointed aloft in endless variations, has 35,000 followers (although some may just be there for the swimwear shots).

But, rather than aiming to whittle the body into a fashionable shape by burning maximum calories, the emphasis of gymnastics is on flexibility, movement and strength. Gymnasts’ bodies may look unachievable, but Tan – who looks as if he probably sleeps in a human-flag pose – believes that “this is the way that, as animals, our bodies should naturally be”.

He and his wife (and Forma cofounder), Claire Berthier, are osteopaths and are all too familiar with the aches and pains incurred by sitting still. This is what inspired the pair – who used to be a martial arts teacher and dancer respectively – to start teaching gymnastics. “I would listen to people getting upset about their back pain,” says Tan, “but I could only make them feel better temporarily.” “They were never going to see long-term improvements without getting off their arses and putting in some hard work themselves.”

They started by teaching a small clutch of their osteopathy clients, who told their friends. Forma now offers multiple daily classes at two sites in Gloucestershire, where Tan and Berthier live, regularly attended by a community stretching across the south-west and the Midlands to London. Gymnastics Bodies online members visit from all over Europe, for intensive weeks of classes, and occasional weekenders for which Sommer flies over to take classes. Forma takes the method to London, too, with workshops at the Rambert dance company.

Surprisingly, Forma classes are not intimidating. There are plenty of people in their 40s, 50s and 60s, working at their own pace, some overcoming injuries only to find themselves, after a few months, strong and supple enough to hold the rings and turn their bodies upside down, or even do the splits.

Tan is convinced that gymnastics training could see many people into old age in comfort – certainly, it isn’t unusual to see gymnasts in their 80s, still as strong as oxen. The world’s oldest competing gymnast – 91-year-old Johanna Quaas – still puts on an awe-inspiring show. In 2006, researchers in Finland studied 117 women with an average age of 62, over six years and found, perhaps predictably, that those who did recreational gymnastics maintained superior bone density, bone strength and muscular agility.

Most Forma classes are called Foundations, and start with a warm up, travelling around the studio in various increasingly taxing ways. Running with high knees and then heel flicks (pointing your toes up behind you as you prance). Side sashays next, various lunges and then crawling without your knees touching the ground, and stiff-leg bears come next – crawling with straight legs, made fun by the name. Then comes my nemesis: walking on hands and feet with your back facing the ground, but as straight as a table top. Taxing is not the word.

Warm up done, everyone finds a partner to start the fun stuff – though no two classes are the same. There might be strength-building planks on parallette bars, or a bridge while holding on to your partner’s ankles, who can then help you increase your back bend by lifting your waist a little higher for you. Then there are any number of no-messing core strengthening drills, before attempting something more adventurous on the rings or bars – working towards that flag (in my head, at least).

Specialist handstand and rings classes are run separately, but you need to have built strength in the Foundations classes first. Essentially, you’re training your body so you can get back on the climbing frame. “That’s the best thing about it,” says Tan. “You get to play like a kid again.”